HID: add ThingM blink(1) USB RGB LED support

The ThingM blink(1) is an open source hardware USB RGB LED. It contains
an internal EEPROM, allowing to configure up to 12 light patterns. A
light pattern is a RGB color plus a fade time. This driver registers a
LED class instance with additional sysfs attributes to support basic
functions such as setting RGB colors, fade and playing. Other functions
are still accessible through the hidraw interface.

At this time, the only documentation for the device is the firmware
source code from ThingM, plus a few schematics. They are available at:

https://github.com/todbot/blink1



This patch is version 3. It updates the name of the source file, the
driver and the led sysfs entry, according to comments from Jiri Kosina
and Simon Wood.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>